Quoted from: Ji, D., L. Wang, J. Feng, Q. Wu, H. Cheng, Q. Zhang, J. Yang et al. "Description and basic evaluation of Beijing Normal University Earth System Model (BNU-ESM) version 1." Geoscientific Model Development 7, no. 5 (2014).  https://gmd.copernicus.org/articles/7/2039/2014/gmd-7-2039-2014.pdf 

Climate models are the essential tools to investigate the response of the climate system to various forcings, to make climate predictions on seasonal to decadal time scales and to make projections of future climate (Flato et al., 2013). At Beijing Normal University, with collaboration from several model development centers in China, the BNU-ESM (Beijing Normal University Earth System Model) comprising atmospheric, land, oceanic, and sea ice components along with carbon cycles has recently been developed. The development of BNU-ESM was prompted by foundation of a new multidisciplinary research center committed to study global change and earth system science in Beijing Normal University. The BNU-ESM takes advantage of contemporary model achievements from several well-known modeling centers, and its components were chosen based on the specific expertise and experience available to the research center, and furthermore with an eye to how the research strengths of the center can improve and develop it.

The coupling framework of BNU-ESM is based on an interim version of the Community Climate System Model version 4 (CCSM4) (Gent et al., 2011; Vertenstein et al., 2010) developed at the National Center for Atmospheric Research (NCAR) on behalf of the Community Climate System Model/Community Earth System Model (CCSM/CESM) project of the University Corporation for Atmospheric Research (UCAR). Notably, BNU-ESM differs from CCSM4 in the following major aspects: (i) BNU-ESM utilizes the Modular Ocean Model version 4p1 (MOM4p1) (Griffies, 2010) developed at Geophysical Fluid Dynamics Laboratory (GFDL). (ii) The land surface component of BNUESM is the Common Land Model (CoLM) (Dai et al., 2003, 2004; Ji and Dai, 2010) initially developed by a community and further improved at Beijing Normal University. (iii) The CoLM has a global dynamic vegetation sub-model and terrestrial carbon and nitrogen cycles based on the Lund–Potsdam–Jena model (LPJ) (Sitch et al., 2003) and the Lund–Potsdam–Jena Dynamic Nitrogen scheme (LPJ-DyN) (Xu and Prentice, 2008). The LPJ-DyN based terrestrial carbon and nitrogen interaction schemes are very different from the biogeochemistry Carbon-Nitrogen scheme used in CLM4 or CCSM4 (Thornton and Rosenbloom, 2005; Oleson et al., 2010; Lawrence et al., 2011). (iv) The atmospheric component is an interim version of the Community Atmospheric Model version 4 (CAM4) (Neale et al., 2010, 2013) modified with a revised Zhang–McFarlane deep convection scheme (Zhang and McFarlane, 1995; Zhang, 2002; Zhang and Mu, 2005a). (v) The sea ice component is the Community Ice CodE (CICE) version 4.1 (Hunke and Lipscomb, 2010) developed at Los Alamos National Lab (LANL), while the sea ice component of CCSM4 is based on Version 4 of CICE. These variations illustrate how the BNU-ESM adds to the much-desired climate model diversity, and thus to the hierarchy of models participating in the Climate Model Intercomparison Projects phase 5 (CMIP5) (Taylor et al., 2012).

As a member of CMIP5, BNU-ESM has completed all core simulations within the suite of CMIP5 long-term experiments and some of related tier-1 integrations intended to examine specific aspects of climate model forcing, response, and processes. The long-term experiments performed with BNU-ESM include a group forced by observed atmospheric composition changes or specified concentrations (e.g., piControl, historical, rcp45 and rcp85 labeled by CMIP5), and a group driven by time-evolving emissions of constituents from which concentrations can be computed interactively (e.g., esmControl, esmHistorical and esmrcp85 labeled by CMIP5). At the same time, BNU-ESM joined the Geoengineearing Model Intercomparison Project (GeoMIP) and completed its first suite of experiments (G1–G4; Kravitz et al., 2011) concentrating on solar radiation management (SRM) schemes (e.g., Moore et al., 2014). Data for all CMIP5 and GeoMIP simulations completed by BNU-ESM

have been published via an Earth System Grid Data Node located at Beijing Normal University (BNU) and can be accessed at http://esg.bnu.edu.cn, as a part of internationally federated, distributed data archival and retrieval system, referred to as the Earth System Grid Federation (ESGF).

Many studies have utilized CMIP5 results from BNUESM, and the model has received comprehensive evaluations. For example, Wu et al. (2013) evaluated the precipitation-surface temperature (P–T ) relationship of BNU-ESM among 17 models in CMIP5 and found BNUESM has better ability in simulating P–T pattern correlation than other models, especially over ocean and tropics. Bellenger et al. (2013) used the metrics developed within the Climate Variability and Predictability (CLIVAR) Pacific Panel and additional metrics to evaluate the basic El NiñoSouthern Oscillation (ENSO) properties and associated feedbacks of BNU-ESM and other CMIP5 models. BNU-ESM performs well on simulating precipitation anomalies over the Niño-4 region; the ratio between the ENSO spectral energy in the 1–3 year band and in 3–8 year band is well consistent with observational result, but the model has stronger sea surface temperature (SST) anomalies than observational estimates over Niño-3 and Niño-4 regions. Fettweis et al. (2013) reported BNU-ESM can simulate the 1961–1990 variability of the June–August (JJA) North Atlantic Oscillation (NAO) well and the sharp decrease of the NAO index over the last 10 years as observed, and the model projects similar negative NAO values into the future under RCP 8.5 scenario. Gillett and Fyfe (2013) reported no significant Northern Annular Mode (NAM) decrease in any season between 1861 and 2099 in historical and rcp45 simulations of BNU-ESM as with the other 36 models from CMIP5. Bracegirdle et al. (2013) assessed the model’s simulation of near-surface westerly winds over the Southern Ocean and found an equatorward bias in the present-day zonal mean surface jet position in common with many of the CMIP5 models. Among other studies, Chen et al. (2013) evaluated the cloud and water vapor feedbacks to El Niño warming in BNU-ESM. Vial et al. (2013) diagnosed the climate sensitivity, radiative forcing and climate feedback of BNU-ESM. Roehrig et al. (2013) assessed the performance of BNU-ESM on simulating the West African Monsoon. Sillmann et al. (2013) evaluated the model performance on simulating climate extreme indices defined by the Expert Team on Climate Change Detection and Indices (ETCCDI). Wei et al. (2012) utilized BNU-ESM in assessment of developed and developing world responsibilities for historical climate change and CO2 mitigation.

Although the simulation results from BNU-ESM are widely used in many climate studies, a general description of the model itself and its control climate is still not available. Documenting the main features of the model structure and its underlying parameterization schemes will help the climate community to further understand the results from BNU-ESM.